There are some conventional methods known for decorating a resin product as well as giving it a hard coating property such as abrasion resistance and high surface hardness. One of the methods is such that a decorated sheet for an injection molding, which is laminated with a print layer, decoration layer made of a vapor-deposited layer or the like, and hard coating layer made of UV curable resin in sequence, is attached to a base film at the time of forming shapes of the resin product. Another method is such that a base film, which is provided with a decorated layer on one side and a hard coating layer on the other side and is further provided with an adhesive layer on the decorated layer, is attached to the product at the time of forming shapes of the product. The base film may be a film made of resin. From the viewpoint of characteristics and prices, a biaxially-oriented polyester film is typically employed. To improve the adhesiveness between the base film and the print layer or the hard coating layer, the base film is provided with an adhesive layer generally.
However, conventional laminated polyester films provided with the adhesive layer might exhibit an insufficient adhesiveness between the laminated polyester film and the print layer or hard coating layer. Further, if exposed to a high temperature and high humidity for a long time, the adhesiveness between the adhesive layer and print layer or the adhesiveness between the adhesive layer and hard coating layer might decrease. Because laminated polyester films are used for housings of cell-phones and electric appliances, a hygrothermal adhesiveness, which means an adhesiveness determined after exposed to a high temperature and high humidity, as well as adhesiveness under a normal condition is required to be excellent.
Furthermore, in the case of generating defects with attached dust and deteriorating a handling performance, caused by static electricity generated in the manufacturing process of laminated polyester films, the adhesive layer is required to be given an antistatic property.
Furthermore, even the transparency of the laminated polyester film as well as the base film and adhesive layer constituting the laminated polyester film is important to reflect a color and texture of the decorated layer to the resin product.
To solve such problems, WO 2007/032295 discloses a method where the adhesive layer is constituted by acrylic urethane copolymer resin, polyester resin, and cross-linking agent. JP 2006-206802 A discloses a method where the adhesive layer is constituted by a water-soluble resin containing acrylic urethane copolymer resin, and cross-linking agent. However, the technologies disclosed in WO '295 and JP '802 cannot satisfy both of the antistatic property and adhesiveness sufficiently. JP 2009-083456 A discloses a method where the adhesive layer is constituted by conductive polymer resin, acrylic resin, cross-linking agent and fluorine resin. However, the technology disclosed in JP '456 relates to adhesiveness to adhesive tapes, and the technology might exhibit insufficient adhesiveness with respect to the hard coating layer or print layer made of a print ink.
Accordingly, it could be helpful to provide laminated polyester film, forming member, formed body and manufacturing method thereof wherein the laminated polyester film is excellent in transparency, adhesiveness to a print layer or a hard coating layer and antistatic property, and the excellent adhesiveness and antistatic property can be maintained even after forming shapes.